I was comparing two different groups, and in one, my n was 1600, and the other n was around 700. I found pretty much all significant differences, but is that maybe due to sample size. I tried doing a random selection making the sample sizes equal (both around 700) and got more or less the same numbers and significance every time. Should I do anything else, or is this fine? I also bootstrapped within one of these restricted sets and got about the same numbers.